It is not a sport similar to snowboarding or skateboarding. Waterboading is where a person is strap on a board in a position of lying down and water is poured on his/her cloth covered mouth to impart a sense of drowning. Waterboarding is an act of torture usually by captures during war which is considered as illegal by the world community. And yet the goldstandard of double standard is seen where US is practicing the torture and don't want anybody else to use the method against themselve. Whatever the case is the act of waterboarding is a form of torture and it is illegal.